Mail security has become increasingly important in a society where fraud is rampant and identity theft is commonplace. Theft of checks and other valuables from delivered mail is not uncommon, particularly in many urban areas. Customers of the United States Postal Service, for example, routinely receive deliveries of blank checks, credit cards, government checks (e.g., Social Security checks), as well as other material having monetary worth or which may be useful in perpetrating fraud in one way or another.
Heretofore, there has been little to protect the recipient of mail from criminals or other mischievous persons intent on stealing or otherwise tampering with delivered mail.